/*
 * Copyright (C) 2009, 2010 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License (not later!)
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program; if not,  see <http://www.gnu.org/licenses>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "event-parse.h"
#include "event-utils.h"

static struct func_stack {
        int size;
        char **stack;
} *fstack;

static int cpus = -1;

#define STK_BLK 10

struct pevent_plugin_option plugin_options[] =
{
        {
                .name = "parent",
                .plugin_alias = "ftrace",
                .description =
                "Print parent of functions for function events",
        },
        {
                .name = "indent",
                .plugin_alias = "ftrace",
                .description =
                "Try to show function call indents, based on parents",
                .set = 1,
        },
        {
                .name = NULL,
        }
};

static struct pevent_plugin_option *ftrace_parent = &plugin_options[0];
static struct pevent_plugin_option *ftrace_indent = &plugin_options[1];

static void add_child(struct func_stack *stack, const char *child, int pos)
{
        int i;

        if (!child)
                return;

        if (pos < stack->size)
                free(stack->stack[pos]);
        else {
                char **ptr;

                ptr = realloc(stack->stack, sizeof(char *) *
                              (stack->size + STK_BLK));
                if (!ptr) {
                        warning("could not allocate plugin memory\n");
                        return;
                }

                stack->stack = ptr;

                for (i = stack->size; i < stack->size + STK_BLK; i++)
                        stack->stack[i] = NULL;
                stack->size += STK_BLK;
        }

        stack->stack[pos] = strdup(child);
}

static int add_and_get_index(const char *parent, const char *child, int cpu)
{
        int i;

        if (cpu < 0)
                return 0;

        if (cpu > cpus) {
                struct func_stack *ptr;

                ptr = realloc(fstack, sizeof(*fstack) * (cpu + 1));
                if (!ptr) {
                        warning("could not allocate plugin memory\n");
                        return 0;
                }

                fstack = ptr;

                /* Account for holes in the cpu count */
                for (i = cpus + 1; i <= cpu; i++)
                        memset(&fstack[i], 0, sizeof(fstack[i]));
                cpus = cpu;
        }

        for (i = 0; i < fstack[cpu].size && fstack[cpu].stack[i]; i++) {
                if (strcmp(parent, fstack[cpu].stack[i]) == 0) {
                        add_child(&fstack[cpu], child, i+1);
                        return i;
                }
        }

        /* Not found */
        add_child(&fstack[cpu], parent, 0);
        add_child(&fstack[cpu], child, 1);
        return 0;
}

static int function_handler(struct trace_seq *s, struct pevent_record *record,
                            struct event_format *event, void *context)
{
        struct pevent *pevent = event->pevent;
        unsigned long long function;
        unsigned long long pfunction;
        const char *func;
        const char *parent;
        int index;

        if (pevent_get_field_val(s, event, "ip", record, &function, 1))
                return trace_seq_putc(s, '!');

        func = pevent_find_function(pevent, function);

        if (pevent_get_field_val(s, event, "parent_ip", record, &pfunction, 1))
                return trace_seq_putc(s, '!');

        parent = pevent_find_function(pevent, pfunction);

        if (parent && ftrace_indent->set)
                index = add_and_get_index(parent, func, record->cpu);

        trace_seq_printf(s, "%*s", index*3, "");

        if (func)
                trace_seq_printf(s, "%s", func);
        else
                trace_seq_printf(s, "0x%llx", function);

        if (ftrace_parent->set) {
                trace_seq_printf(s, " <-- ");
                if (parent)
                        trace_seq_printf(s, "%s", parent);
                else
                        trace_seq_printf(s, "0x%llx", pfunction);
        }

        return 0;
}

int PEVENT_PLUGIN_LOADER(struct pevent *pevent)
{
        pevent_register_event_handler(pevent, -1, "ftrace", "function",
                                      function_handler, NULL);

        traceevent_plugin_add_options("ftrace", plugin_options);

        return 0;
}

void PEVENT_PLUGIN_UNLOADER(struct pevent *pevent)
{
        int i, x;

        pevent_unregister_event_handler(pevent, -1, "ftrace", "function",
                                        function_handler, NULL);

        for (i = 0; i <= cpus; i++) {
                for (x = 0; x < fstack[i].size && fstack[i].stack[x]; x++)
                        free(fstack[i].stack[x]);
                free(fstack[i].stack);
        }

        traceevent_plugin_remove_options(plugin_options);

        free(fstack);
        fstack = NULL;
        cpus = -1;
}